The present invention relates to charger control in a portable electronic device, and more particularly, to an apparatus for performing hybrid power control in an electronic device.
FIG. 1 illustrates a conventional charger system according to the related art, where this conventional charger system may be implemented within a conventional multifunctional mobile phone for charging a battery thereof, such as that coupled to the terminal VBAT. The conventional charger system may comprise some switching units such as the Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) M1, M2, MA, and MB, some drivers such as those driving these MOSFETs M1, M2, MA, and MB through their gate terminals, and some switching control circuits such as the control circuit Ctrl_A arranged for controlling switching operations of the MOSFETs M1 and M2, the control circuit Ctrl_1 arranged for controlling switching operations of the MOSFET MA and MB, and the control circuit Ctrl_2 arranged for controlling switching operations of the MOSFET coupled between the terminals VSYS and VBAT. For example, when the user is taking a photo with the flash, this conventional charger system may perform a reverse boost operation and output power through the flash path (labeled “FLASH path by reverse boost” in FIG. 1, for better comprehension) toward the light emitting diodes (LEDs) shown around the lower right corner of FIG. 1, and the MOSFETs M21 and M22 may be utilized as the trigger module of the flash. In another example, when the user is using the LEDs as a torch, rather than the flash for photography, this conventional charger system may output power through the torch path (labeled “TORCH path by VSYS” in FIG. 1, for better comprehension) toward the LEDs, and the MOSFETs M23 and M24 may be utilized as the switching module of the torch. Please note that this conventional charger system may be suitable for the conventional multifunctional mobile phone in a situation where the input voltage at the terminal VIN for obtaining external power from outside the conventional multifunctional mobile phone is greater than a typical flash voltage level on the flash path since one of the MOSFETs M1 and M2 with different body diode directions may fully block the path between the terminals VIN and VM to protect the components within the conventional charger system. However, during charging the battery by using an external power supply such as an alternating current/direct current (AC/DC) adapter, the series of resistance due to the MOSFETs M1, M2, and MA is large, which typically reduces the power efficiency on the power transmission path from the terminal VIN to the terminal VSYS.
FIG. 2 illustrates another conventional charger system according to the related art, where this conventional charger system may also be implemented within the conventional multifunctional mobile phone for charging the battery thereof, such as that coupled to the terminal VBAT. The MOSFET M2 shown in FIG. 1 is absent in the conventional charger system shown in FIG. 2, and the control circuit Ctrl_A described above is replaced by the control circuit Ctrl_B arranged for controlling switching operations of the MOSFET M1. In comparison with the conventional charger system shown in FIG. 1, as the number of MOSFETs on the path between the terminals VIN and VM is reduced, the power efficiency on the power transmission path from the terminal VIN to the terminal VSYS in the conventional charger system shown in FIG. 2 is greater than that of the architecture shown in FIG. 1. However, the MOSFET M1 cannot fully block the path between the terminals VIN and VM in each of various situations. For example, the body diode direction of the MOSFET M1 may be equivalent to the direction from the terminal VIN to the terminal VM, and the reverse boost voltage level at the terminal VM for flash usage must be higher than the input voltage level at the terminal VIN. As a result, the power efficiency on the power transmission path from the terminal VSYS to the terminal VM is poor.
In conclusion, there are many problems in the conventional charger systems, and each of the conventional charger systems cannot guarantee high power efficiency in each of various situations. Thus, a novel architecture is required to improve the power efficiency, in order to guarantee the overall performance of the whole system.